The present invention relates to a dimension measuring device that measures dimensions, such as inner diameters, outer diameters and depths, and displays the measured dimension measurements and, more particularly, to a dimension measuring device that commonly displays, in a bar graph etc., plural dimension measurements measured by plural dimension measuring sections.
In a machining device or processing device, the state of machining or processing is managed by measuring dimensions of each portion. For each portion to be measured, a tolerance, which is an allowable dimension range, is specified and it is required for a dimension measurement to be within this tolerance. In order to make it easy to judge that a dimension measurement is within a tolerance, the dimension measurement is displayed in a graph and an upper limit value and a lower limit value of the tolerance are displayed in accordance with the graph. A typical graphic display is a bar graph display. Although the present invention is not limited to a bar graph display, explanation is given here using, as an example, a bar graph display. The display of a dimension measurement in a bar graph is described in, for example, Japanese Unexamined Patent Publication (Kokai) No. 4-64011 and Japanese Unexamined Patent Publication (Kokai) No. 7-334113, therefore, a detailed explanation is not given here. By the way, because a bar graph uses an LED, an LCD (Liquid Crystal Display), etc., it becomes expensive.
Methods for measuring dimensions at each portion include various types and the present invention can be applied to any type of dimension measuring device. Respective methods for measuring dimensions are widely known and, therefore, an explanation is not given here.
Conventionally, in a dimension measuring device that displays a bar graph, a dimension measuring section corresponds, one to one, to a bar graph. In other words, the number of dimension measuring sections and the number of bar graphs are equal. A more general configuration is such one in which a dimension measuring unit having one dimension measuring section is connected to a column having one bar graph. A dimension measuring unit is connected to a column via cable and connector and various dimension measuring units can be connected thereto in accordance with objects to be measured. It has been proposed recently that a dimension measuring unit and a column are connected by a radio communication channel.
However, in a manufacturing process etc., there are cases where plural objects are measured in the same process and if a dimension measuring device is provided for each object to be measured, the facility cost is increased and a large space is required, resulting in a problem of poor usability. Therefore, a configuration has been suggested in which plural bar graphs are provided in a column and plural dimension measuring units are connected, however, such a configuration is just one in which conventional dimension measuring devices are simply combined and it cannot solve the problem that the cost is increased. By the way, as a modification example of such a configuration, there may be a case where one dimension measuring unit is provided with plural dimension measuring sections for measuring dimensions of plural portions and in such a case, a column having plural bar graphs is used.
In order to solve the above-mentioned problems, a dimension measuring device has been proposed in which plural dimension measuring units are connected to a column having one bar graph and it is made possible to select a dimension measurement to display in a bar graph by a switch. As this device uses only one expensive bar graph, the effect of a reduction in cost is more significant compared to a case where plural bar graphs are used. By the way, there may be a case where a column is provided with plural bar graphs, more dimension measuring units (sections) in number than bar graphs are connected, and a dimension measurement to display is selected by a switch, however, for simplicity of explanation, an example in which a column is provided with one bar graph is taken here. Further, there may be a case where one dimension measuring unit has plural dimension measuring sections and in the following explanation, it is assumed that the dimension measuring section is connected to the column.
As described above, in a manufacturing process, it is important to confirm that a dimension measurement is within a tolerance and the upper limit value and the lower limit value of the tolerance are displayed in accordance with a bar graph. Japanese Unexamined Patent Publication (Kokai) No. 4-64011 has described a configuration for automatically producing a display in which the center value of a bar graph and the center value of a tolerance coincide with each other in a bar graph display. Due to this configuration, the display range by a bar graph can be effectively utilized.